Hydraulic Coupling Member With Pressure-Relieving Poppet Valve

ABSTRACT

A poppet valve for a hydraulic coupling member has an internal, spring-loaded check valve (which may be a ball check valve) in fluid communication with a bleed passage. The check valve may be configured as a pressure-relief valve which bleeds off excess hydraulic fluid pressure within the coupling member to a preselected value. A poppet valve according to the invention may be used in female coupling members and/or male coupling members. Certain embodiments of the invention may be retrofitted to coupling members of the prior art.

CROSS-REFERENCE TO RELATED APPLICATIONS:

This application claims the benefit of U.S. Provisional Application No.61/511,326, filed on Jul. 25, 2011.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT: NotApplicable BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to hydraulic coupling members. More particularly,it relates to male and female hydraulic coupling members equipped withinternal, spring-loaded poppet valves for controlling the flow ofhydraulic fluid.

2. Description of the Related Art Including Information Disclosed Under37 CFR 1.97 and 1.98

A wide variety of hydraulic couplings include internal poppet valves forpreventing the loss of hydraulic fluid when the coupling isdisconnected. Hydraulic couplings designed for subsea use also commonlyemploy poppet valves for preventing seawater from entering the hydraulicsystem when the coupling members are de-mated. In many designs, thepoppet valves include mechanical valve actuators which cause valves thatare spring-loaded to the closed position to open upon coupling make-up.

U.S. Pat. Nos. 4,900,071 and 5,052,439 disclose an undersea hydrauliccoupling which includes a male member and female member and a two-pieceretainer for restraining radial movement of a wedge-shaped annular sealinto the central bore of the female member. The two-piece retainerincludes a cylindrical retainer sleeve member that slides within thefemale member bore, and a threaded retainer-locking member which engagesthreads in the wall of the central bore. The retainer-locking memberholds the retainer sleeve member in place within the female member bore.The annular seal is restrained from radial movement by a dovetailinterfit with a mating shoulder on at least one of the retainer sleeveand the retainer-locking members.

U.S. Pat. No. 5,360,035 discloses an undersea hydraulic coupling havinga poppet valve movable between an open and a closed position. The poppetvalve is pressure balanced—i.e., it operates without substantial fluidpressure exerted axially against the face of the poppet valve. When thepoppet valve is opened, radial passages are interconnected through anannular cavity between the poppet valve body and the valve bore.

U.S. Pat. No. 5,692,538 discloses an undersea hydraulic coupling memberhaving angled flow ports to prevent ingress of debris into the hydrauliclines and having a bleed passage to allow trapped hydraulic fluid tobleed off when the coupling members are disconnected. The poppet valvein combination with the angled flow ports helps keep the hydraulicsystem clear of debris when the members are disconnected.

U.S. Pat. No. 6,085,785 discloses an undersea hydraulic coupling havingan extended probe section. The male member of the coupling houses avalve spring having a larger diameter than the diameter of the valvebody. The valve spring is configured to close the valve to preventingress of sea water or leakage of hydraulic fluid from the system. Oneor more seals engage the extended probe section.

U.S. Pat. No. 6,095,191 discloses an undersea hydraulic coupling havinga male member with a tapered, frusta-conical surface and a female memberwith a tapered, frusta-conical bore. Before radial seals engage thefrusta-conical surfaces, trapped seawater is expelled or displaced fromthe bore through the space between the coupling members, therebypreventing seawater from entering hydraulic lines.

U.S. Pat. No. 6,474,359 discloses an undersea hydraulic coupling memberhaving a bleed valve which opens to allow hydraulic fluid trapped in thecoupling member to escape until the pressure is below a predeterminedlevel. The coupling member employs a poppet valve within a sleeve.

U.S. Pat. No. 6,375,153 discloses an undersea hydraulic coupling havinga stepped internal bore dimensioned to increase the flow rate throughthe coupling. The coupling allows an increased flow rate withoutincreasing the size or weight of the coupling by positioning the poppetvalve in the body section, rather than in the probe section, of the malecoupling member.

U.S. Pat. No. 6,237,632 discloses an undersea hydraulic coupling memberhaving a primary poppet valve and a secondary poppet valve to improvereliability against leakage when the coupling members are separated. Aspring extends between the first poppet valve and the actuator for thesecond poppet valve. The secondary poppet valve remains closed unlessthe first poppet valve is fully opened, so that debris or other materialthat could prevent sealing of the first poppet valve will not causeleakage of hydraulic fluid through the second poppet valve.

U.S. Pat. No. 6,357,722 discloses an undersea hydraulic coupling havinga poppet valve with an actuator extending from the valve and a guidebetween the actuator and bore. The guide is a sleeve-shaped memberaround the actuator with flow passages which ensure a smooth flow ofhydraulic fluid through the annulus between the coupling bore andactuator. The guide also helps prevent damage to the actuator, andaligns the actuator during connections, disconnections and use.

U.S. Pat. No. 6,283,444 discloses an undersea hydraulic coupling memberhaving a valve actuator which extends through the probe section and theleading face, and has angled flow ports in the probe section which helpkeep the hydraulic system clear of debris when the coupling members aredisconnected subsea.

U.S. Pat. No. 6,227,245 discloses an undersea hydraulic coupling memberwhich has angled flow ports to prevent ingress of debris into thehydraulic lines. A port guard attached to the valve actuator closes theflow ports unless the poppet valve is opened by mutual engagement withan opposing coupling member.

U.S. Pat. No. 6,626,207 discloses an undersea hydraulic coupling withinterlocking poppet valve actuators. The actuators extend from thepoppet valves of each coupling member and interlock to resist bendingand/or other lateral displacement caused by hydraulic fluid flow andturbulence in the coupling member bores and at the junction between thecoupling members.

U.S. Pat. No. 6,631,734 discloses a dummy undersea hydraulic couplingmember for protecting an opposing undersea hydraulic coupling memberwhen the hydraulic lines are not operating. The dummy undersea hydrauliccoupling member has a water displacement expansion chamber with a pistontherein that allows trapped water and/or air to move from the receivingchamber to the water displacement expansion chamber during connection ofthe dummy coupling member to the opposing coupling member. The dummycoupling member may include a normally-closed poppet valve in the waterdisplacement expansion chamber which blocks water and/or air from movingbetween the receiving chamber and the water displacement expansionchamber in the closed position. The poppet valve opens in response towater and/or air pressure acting upon it.

U.S. Pat. No. 7,159,616 discloses a dual-path hydraulic coupling. Afemale hydraulic coupling member comprises a first flow port; a secondflow port; a third flow port in fluid communication with both the firstflow port and the second flow port; a first poppet valve for opening andclosing the first flow port; and a second poppet valve for opening andclosing the second flow port, the second poppet valve being connected tothe first poppet valve such that the second poppet valve moves to theclosed position when the first poppet valve is open and moves to theopen position when the first poppet valve is closed.

U.S. Pat. No. 7,913,974 discloses male and female hydraulic couplingmembers which have an internal poppet valve that is held in the closedposition by a flat wire, helical compression spring. The spring isconfigured such that when the poppet valve is moved to its fully openposition, the coils of the spring are completely compressed therebyforming a substantially smooth bore tube for the flow of hydraulicfluid. The flat wire, helical compression spring may also act as a valvestop, limiting movement of the poppet valve and providing the necessaryresistance to move the valve actuator of a corresponding valve in amating member.

In the subsea hydraulic couplings of the prior art, damage can occurwhen a coupling member is raised from depth due to the change in thedifferential pressure between the hydraulic fluid within the couplingand the ambient pressure—i.e., the pressure due to the water columnand/or atmospheric pressure. The present invention solves this problem.

BRIEF SUMMARY OF THE INVENTION

A spring-loaded poppet valve for a hydraulic coupling member has aninternal, spring-loaded check valve (which may be a ball check valve) influid communication with a bleed passage. The check valve may beconfigured to bleed off hydraulic fluid pressure within the couplingmember to a preselected value. A poppet valve according to the inventionmay be used in female coupling members and/or male coupling members.Certain embodiments of the invention may be retrofitted to couplingmembers of the prior art.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

FIG. 1 is a cross-sectional view of a female hydraulic coupling equippedwith a poppet valve according to the prior art.

FIG. 2 is a cross-sectional view of a female hydraulic coupling memberequipped with a pressure-relieving poppet valve according to a firstembodiment of the invention shown in the closed position.

FIG. 3 is an enlarged view of the portion indicated in FIG. 2.

FIG. 4 is a cross-sectional view of a pressure-relieving poppet valveaccording to a first embodiment of the invention shown with its reliefvalve in the closed position.

FIG. 5A is a perspective view of a pressure-relieving poppet valveaccording to a first embodiment of the invention.

FIG. 5B is a perspective view of a pressure-relieving poppet valveaccording to a second embodiment of the invention.

FIG. 6 is a cross-sectional view of a female hydraulic coupling memberequipped with a pressure-relieving poppet valve according to a thirdembodiment of the invention shown in the closed position.

FIG. 7A is a perspective view of a pressure-relieving poppet valveaccording to a third embodiment of the invention.

FIG. 7B is a perspective view of a pressure-relieving poppet valveaccording to a fourth embodiment of the invention.

FIG. 8A is a cross-sectional view of a male hydraulic coupling memberequipped with a pressure-relieving poppet valve according a thirdembodiment of the invention (shown in FIG. 7A).

FIG. 8B is a cross-sectional view taken along line 8B in FIG. 8A.

DETAILED DESCRIPTION OF THE INVENTION

As shown in FIG. 1, a female coupling member 20 of the prior artcomprises body 21, handle 48 which may be secured to a manifold plate orthe like, and central bore 32 which has several variations in itsdiameter as it extends through the female member. The first end of thebore may be internally threaded for connection to a hydraulic line.Other connection means known in the art may be utilized includingwelding, swaging, compression fittings, and the like. A cylindricalpassageway extends longitudinally within the female member body andterminates at valve seat 27. Adjacent valve seat 27 is shoulder 33 whichforms one end of receiving chamber 34.

In the coupling illustrated in FIG. 1, the receiving chamber whichreceives the probe of the male member has a stepped internal diameterwith internal shoulders 33, 35 and 63. The receiving chamber has a firstsmaller diameter 43 and a second larger diameter 47.

The female member 20 includes poppet valve 28 which is sized to slidewithin the cylindrical passageway. The poppet valve may be conical inshape and is urged by valve spring 41 into a seated position againstvalve seat 27. When the poppet valve is in a closed position against thevalve seat, it prevents fluid from flowing between the male member andthe female member. Hollow spring seat 42 anchors the valve spring 41 andis held in place by clip 45. Actuator 44 extends from the apex of thepoppet valve.

Ring shaped seal 50 is positioned in the receiving chamber of the femalemember. The ring shaped seal may be an elastomer or other polymer sealthat is flexible and resilient. In other couplings of the prior art,seal 50 is fabricated from an engineering plastic such aspolyetheretherketone (PEEK). Seal 50 has a first inclined shouldersurface 52 and a second inclined shoulder surface 51. The axialthickness of the elastomeric seal at its outer circumference (adjacentelement 69 in FIG. 1) is greater than the axial thickness of the seal atinner circumference 67. The seal thus has a generally wedge-shaped crosssection. Seal 50 may have one or more radial sealing surfaces 55, 56extending inwardly from the seal's inner circumference 67. Each of theradial sealing surfaces extends inwardly from the inner circumference soas to engage the probe of the male member when the probe is insertedthrough the seal. The radial sealing surfaces may be elasticallydeformed by the probe when it is inserted through the seal. The radialsealing surfaces 55 and 56 provide guide points to help align and guidethe probe of the male member when it is inserted through the seal andinto the receiving chamber 34.

In the prior art female coupling member illustrated in FIG. 1, probeseal 50 has grooves in its outer circumference. O-rings 57, 58 orsimilar seals may be positioned in each of the grooves. Alternatively,seal 50 may have a plurality of integral sealing projections whichextend from its outer circumference.

In the female coupling member shown in FIG. 1, implosion of the sealinto the receiving chamber due to low pressure or vacuum is resistedbecause the seal has an interlocking fit with reverse inclined shouldersurface 62 of seal retainer 29 and reverse inclined shoulder surface 61of locking member 30. The seal retainer may be a cylindrical sleeve thatslides into the second diameter 47 of the receiving chamber.Alternatively, the seal retainer may be threaded to the female member orengaged to the female member by other means. In the illustratedcoupling, when the seal retainer is fully engaged with the femalemember, first end 46 of the seal retainer abuts shoulder 63. The sealretainer holds hollow radial metal seal 31 on internal shoulder 35.

In the female coupling member illustrated in FIG. 1, the seal retainerhas a first internal circumferential surface 59 adjacent the first endthereof and a second internal circumferential surface 69 adjacent thesecond end thereof. The internal diameter of the first innercircumferential surface is smaller than the internal diameter of thesecond internal circumferential surface. Reverse inclined shoulder 62 issituated between the first and second internal circumferential surfaces.The reverse inclined shoulder has an interlocking fit with seal 50 torestrain the seal from moving inwardly in a radial direction. O-ring 49is positioned in a groove at the first end 46 of the seal retainer toprovide a face-type seal between the seal retainer and shoulder 63.

In the illustrated prior art coupling, locking member 30 engages thefemale coupling member with threads 53. Other engaging means known inthe art may be used. When the locking member is fully secured to thefemale coupling member, first end 64 abuts seal retainer 29 and holdsthe seal retainer in place. The locking member 30 has a central openingwith an internal diameter 54 that allows insertion of the probe of themale member. Reverse inclined shoulder surface 61 holds seal 50 in placeand restrains the seal from moving inward in a radial direction.

The present invention provides an alternative poppet valve design for ahydraulic coupling and may best be understood by reference to thevarious exemplary embodiments shown in the drawing figures whereincorresponding elements share the two, least-significant digits of theirreference numbers.

The pressure-relieving poppet valves of the present invention areequipped with a spring-loaded check valve configured to permitpressurized hydraulic fluid within the coupling to vent from thecoupling until a pre-selected pressure differential between the internaland external pressure is achieved.

A check valve (“non-return valve” or “one-way valve”) is a mechanicaldevice which normally allows fluid (liquid or gas) to flow through it inonly one direction.

Check valves are two-port valves, meaning they have two openings in thebody, one for fluid to enter and the other for fluid to leave. There arevarious types of check valves used in a wide variety of applications.Check valves are often part of common household items. Available in awide range of sizes and costs, check valves may be very small, simple,and/or inexpensive. Check valves work automatically and most are notcontrolled by a person or any external control; accordingly, most do nothave any valve handle or stem.

An important parameter of any check valve is its cracking pressure—theminimum upstream pressure at which the valve will operate. Typically thecheck valve is designed for and can therefore be specified for aspecific cracking pressure.

Although the ball emmberss of ball check valves are most often made ofmetal, they can be made of other materials. In certain specializedcases, they are fabricated of artificial ruby. High pressure pumps andsimilar applications commonly use small inlet and outlet ball checkvalves with both balls and seats made of artificial ruby because of itshardness and chemical resistance. After prolonged use, such check valvescan wear out or the seat can develop a crack, requiring replacement.Therefore, such valves may be made to be replaceable, sometimes placedin a separate body tightly-fitted inside a metal fitting which canwithstand high pressure and which is screwed into the pump head.

There are similar check valves where the moving part is not a ball, butsome other shape, such as a poppet energized by a spring. Ball checkvalves should not be confused with “ball valves,” which are a differenttype of valve in which a ball acts as a controllable rotor to stop ordirect fluid flow.

FIG. 2 depicts a female hydraulic coupling member 120 equipped with apressure-relieving poppet valve 170 according to a first embodiment ofthe invention. Both poppet valve 170 and the pressure-relieving ballcheck valve within the body of the poppet valve are shown in the closedposition.

Female coupling member 120 has a generally cylindrical body 121 with acentral axial bore 132 passing from a first end thereof to an opposingsecond end which forms receiving chamber 134 for receiving the probe ofa corresponding male member (e.g., male member 322 as illustrated inFIG. 8). Central bore 132 may have various sections of differing insidediameters. A frusto-conical section (i.e., a section having the shape ofa conical frustum) may form poppet valve seat 127. As in poppet valvesof the prior art, poppet valve 170 may have radial seal 140 configuredfor sealing engagement with conical valve seat 127, valve actuator 144which moves poppet valve 170 away from seat 127 thereby opening thevalve to the flow of hydraulic fluid when it contacts a correspondingactuator on a male coupling member seated in receiving chamber 134 andvalve spring 141 which is configured to urge poppet 170 to the closedposition by acting against hollow spring seat 142 which may be securedin bore 132 with retainer clip 145. Radial seal 140 may be retainedbetween nose piece 176 and the main section of poppet valve body 171.Radial seal 140 may be a polymer seal. The polymer may be an elastomer.

It will be appreciated by those skilled in the art that poppet valve 170opens and closes by sliding longitudinally within bore 132. Poppet valve170 may be held in alignment within bore 132 by first radial spacer 173and second radial spacer 174. As may best be seen in FIG. 5A, radialspacer 174 may have a plurality of longitudinal slots 193 which, whenthe poppet valve is open, allow hydraulic fluid to flow through annularflow passage 195, through radial flow passageways 177 and into centralbore 172 which is in fluid communication with central bore 132 ofcoupling 120 via the central passageway of hollow spring seat 142. Inthis way, a path for the flow of hydraulic fluid through the coupling isprovided.

In the illustrated embodiment, poppet valve 170 is equipped with a ballcheck valve configured so as to relieve excessive hydraulic pressurewithin coupling 120. The illustrated check valve comprises housing 190,ball 181, valve cage 180, valve spring 185 and spring seat 186.

Poppet valve 170 has a generally cylindrical body 171 with a central,axial bore 172 which may have a plurality of sections with differinginternal diameters. One or more radial fluid passageways 177 providefluid communication between central axial bore 172 and the outercylindrical surface of poppet body 171.

The pressure-relief valve is housed within bore 172 of poppet valve 170.Poppet valve 170 may be considered to have two sections—a first sectionwhich extends from seal 140 (or its equivalent) towards actuator 144(downwards in FIGS. 2 and 4) and a second section which extends fromseal 140 away from valve actuator 144 (upwards in FIGS. 2 and 4). Apressure relief valve 180 according to the present invention iscontained substantially within the second section of poppet valve 170.This permits the relief valve to be larger and to have a larger (andhence stronger) biasing spring 185. This, in turn, allows the provisionof a relief valve having a higher pressure rating—i.e., a highercracking pressure—than would be feasible with a relief valve located inthe first section of poppet valve 170.

Referring now to FIG. 4, it may be seen that the relief valve comprisesa generally tubular member 190 having a central axial bore which mayhave a plurality of sections with differing inside diameters. Shoulder182 separates two such sections and may provide a valve seat for ball181. The outside diameter of tubular member 190 may be sized to permit asliding fit within central axial bore 172 of poppet 170. Valve cage 180bears against ball 181 on a first end and fits within a portion ofspring seat 186 at an opposing, second end. Relief valve spring 185 is acompression spring which bears against the interior end of spring seat186 at one end and against a shoulder on the outer cylindrical surfaceof valve cage 180 at an opposing end. Angled flow passages 184 in valvecage 180 allow hydraulic fluid to flow past ball check valve 181 (whenopen), into central passage 183, thence through nose passageway 188 andout through pressure relief vent 189 which is open to receiving chamber134 of female coupling member 120 (see FIG. 2).

The relief valve may be assembled by inserting ball 181, valve cage 180,valve spring 185 and spring seat 186 into one end of the central cavityof shell member 190. Weld 187 is used in the illustrated embodiment tosecure spring seat 186 to shell 190. In other embodiments, spring stop186 may be in threaded engagement with shell 190. In yet otherembodiments, spring stop 186 may engage shell 190 with an interferencefit.

Also shown in FIGS. 2 and 4 is optional filter 179 disposed in thecentral passageway of valve housing 190. Filter 179 may help to preventany foreign matter in the hydraulic fluid from interfering with theoperation of the relief valve. Filter 179 may comprise a sinteredfilter. Filter 179 may be secured within housing 190 with expander plug178 which may also be used to secure housing 190 within central bore 172of poppet valve 170. As may be best seen in the enlarged view of FIG. 3,the outer, cylindrical surface of housing 190 may include seal 192 andmechanical grippers 191 and 191′ which engage the inner surface of bore172 upon insertion of expander plug 178.

As will be appreciated by those skilled in the art, the crackingpressure of the relief valve is determined in large part by the springconstant of valve spring 185.

FIG. 5B illustrates a second embodiment of the invention wherein poppetvalve 270 comprises radial spacer 274 having a plurality of longitudinalthrough holes 294 which permit the passage of hydraulic fluid into (orout) of the annular space defined by the outer, generally cylindricalsurface of valve body 271 and the inner surface of central bore 132 ofcoupling 120.

FIG. 6 depicts a female hydraulic coupling member 320 equipped with apoppet valve 370 according to a third embodiment of the invention whichpoppet valve incorporates an internal pressure-relieving valve.

Female coupling member 320 has a generally cylindrical body 321 with acentral axial bore 332 passing from a first end thereof to an opposingsecond end which forms receiving chamber 334 for receiving the probe ofa corresponding male member (e.g., male member 322 as illustrated inFIG. 8). Central bore 332 may have a frusto-conical section that formspoppet valve seat 327. As in poppet valves of the prior art, poppetvalve 370 may have radial seal 340 configured for sealing engagementwith conical valve seat 327, valve actuator 344 which moves poppet valve370 away from seat 327 thereby opening the valve to the flow ofhydraulic fluid when it contacts a corresponding actuator on a malecoupling member seated in receiving chamber 334 and valve spring 341which is configured to urge poppet 370 to the closed position by actingagainst hollow spring seat 342 which may be secured in bore 332 withretainer clip 345 which engages a groove in the surface of bore 332.Radial seal 340 may be retained between nose piece 336 and the mainsection of poppet valve body 371. Radial seal 340 may be a polymer seal.The polymer may be an elastomer.

It will be appreciated by those skilled in the art that poppet valve 370opens and closes by sliding longitudinally within bore 332. Poppet valve370 may be held in alignment within bore 332 by first radial spacer 373and second radial spacer 374. As may best be seen in FIG. 7A, radialspacers 373 and 374 may have a plurality of longitudinal slots 393′ and393, respectively, which, when the poppet valve is open, allow hydraulicfluid to flow through annular flow passages 395 and 395′ and intocentral bore 332 of coupling 320. Hydraulic fluid may enter (or exit)coupling 320 via the central passageway of hollow spring seat 342. Inthis way, a path for the flow of hydraulic fluid through the coupling isprovided.

In the illustrated embodiment, poppet valve 370 is equipped a ball checkvalve configured so as to relieve excessive hydraulic pressure withincoupling 320. This pressure-relieving valve comprises valve seat 380,spherical ball 381, ball actuator 397 and valve spring 385 housed withincentral bore 372 of poppet 370.

Poppet valve 370 has a generally cylindrical body with a central, axialbore 372 which may have a plurality of sections with differing internaldiameters. In the illustrated embodiment, nose piece 336 which comprisesvalve actuator 344 is in threaded engagement with one end of poppet body371. The opposing end of poppet body 371 is in threaded engagement (at316) with relief valve seat 380. Seal 318 (which may be an O-ring seal)may be provided to ensure a fluid-tight seal between poppet body 371 andrelief valve seat 380. As shown in FIG. 7A, one or more pairs of wrenchflats 399 may be provided proximate first end 375 of poppet valve 370for installing (or removing) threaded valve seat 380.

Valve member 380 has a central axial bore comprised of a first sectionwhich terminates at shoulder 310 and against which poppet valve spring341 bears and fluid passageway 312 which is open at one end to shoulder310 and has a frusto-conical section 314 at an opposing end which servesas a seat for ball 381.

Valve actuator 397 is configured to slide within central bore 372 ofpoppet 370. It comprises one or more longitudinal passages 398 to permithydraulic fluid to flow from one side thereof to the other. Actuator 397is urged against ball 381 by relief valve spring 385. When the hydraulicfluid pressure in the interior of coupling 320 exceeds a pre-selectedvalue relative to the external pressure, ball 381 will unseat andhydraulic fluid may vent via passages 312 and 398 into central bore 372and then out into receiving chamber 334 via nose passageway 388 andconnecting, angled, pressure relief vent 389.

The pressure-relief valve comprised of elements 380, 381, 397 and 385 issubstantially contained within bore 372 of poppet valve 370. Poppetvalve 370 may be considered to have two sections—a first section whichextends from seal 340 (or its equivalent) towards actuator 344(downwards in FIG. 6) and a second section which extends from seal 340away from valve actuator 344 (upwards in FIG. 6). A pressure reliefvalve according to the present invention is contained substantiallywithin the second section of poppet valve 370. This permits the reliefvalve to be larger and to have a larger (and hence stronger) biasingspring 385. This, in turn, allows the provision of a relief valve havinga higher pressure rating—i.e., a higher cracking pressure—than would befeasible with a relief valve sized to fit within the first section ofpoppet valve 370.

FIG. 7B illustrates a fourth embodiment of the invention wherein poppetvalve 470 comprises radial spacers 473 and 474 having a plurality oflongitudinal through holes 494′ and 494, respectively, which permit thepassage of hydraulic fluid into (or out) of the annular space defined bythe outer, generally cylindrical surface of valve body 471 and the innersurface of central bore 132 of coupling 120 (or central bore 332 ofcoupling 320).

FIGS. 8A and 8B depict a male hydraulic coupling member 322 equippedwith a pressure-relieving poppet valve 370 according to the embodimentof the invention illustrated in FIGS. 6 and 7A. It should be appreciatedthat the other embodiments of a pressure-relieving poppet valveaccording to the invention described above and illustrated in FIGS. 4,5A, 5B and 7B may also be used in male hydraulic coupling members.

As is conventional in the art, male hydraulic coupling member 322comprises a generally cylindrical body 323 having a handle 348 at oneend thereof for connection to a manifold plate or the like and a probemember 324 at an opposing end adapted for insertion into the receivingchamber of a corresponding female coupling member. Body 323 has acentral, axial bore 325 into which pressure-relieving poppet valve 370may be inserted. Central bore 325 may comprise a frusto-conical sectionthat forms poppet valve seat 327. As in poppet valves of the prior art,poppet valve 370 may have radial seal 340 configured for sealingengagement with conical valve seat 327, valve actuator 344 moves poppetvalve 370 away from seat 327 thereby opening the valve to the flow ofhydraulic fluid when it contacts a corresponding actuator in thereceiving chamber of a corresponding female coupling member. Valvespring 341 is configured to urge poppet 370 to the closed position byacting against hollow spring seat 342 which may be secured in bore 325with retainer clip 345.

It will be appreciated by those skilled in the art that poppet valve 370opens and closes by sliding longitudinally within bore 325. Poppet valve370 may be held in alignment within bore 325 by first radial spacer 373and second radial spacer 374. As may best be seen in FIG. 7A, radialspacers 373 and 374 may have a plurality of longitudinal slots 393′ and393, respectively, which, when the poppet valve is open, allow hydraulicfluid to flow through annular flow passages 395 and 395′ and intocentral bore 325 of coupling 322. Hydraulic fluid may enter (or exit)coupling 322 via the central passageway of hollow spring seat 342. Inthis way, a path for the flow of hydraulic fluid through the coupling isprovided.

In the illustrated embodiment, poppet valve 370 is equipped a ball checkvalve configured so as to relieve excessive hydraulic pressure withincoupling 322. This pressure-relieving valve comprises valve seat 380,spherical ball 381, sliding ball actuator 397 and valve spring 385housed within central bore 372 of poppet 370.

Poppet valve 370 has a generally cylindrical body 371 with a central,axial bore 372 which may have a plurality of sections with differinginternal diameters. In the illustrated embodiment, nose piece 336 whichcomprises valve actuator 344 is in threaded engagement with one end ofpoppet body 371. The opposing end of poppet body 371 is in threadedengagement (at 316) with relief valve seat 380. Seal 318 (which may bean O-ring seal) may be provided to ensure a fluid-tight seal betweenpoppet body 371 and relief valve seat 380. As shown in FIG. 7A, one ormore pairs of wrench flats 399 may be provided proximate first end 375of poppet valve 370 for installing (or removing) threaded valve seat380.

Valve member 380 has a central axial bore comprised of a first sectionwhich terminates at shoulder 310 and against which poppet valve spring341 bears and fluid passageway 312 which is open at one end to shoulder310 and has a frusto-conical section 314 at an opposing end which servesas a seat for ball 381.

Valve actuator 397 is configured to slide within central bore 372 ofpoppet 370. It comprises one or more longitudinal passages 398 to permithydraulic fluid to flow from one side thereof to the other. Actuator 397is urged against ball 381 by relief valve spring 385. When the hydraulicfluid pressure in the interior of coupling 322 exceeds a pre-selectedvalue relative to the external pressure, ball 381 will unseat andhydraulic fluid may vent via passages 312 and 398 into central bore 372and then out of the coupling member via nose passageway 388 andconnecting, angled, pressure relief vent 389.

The pressure-relief valve comprised of elements 380, 381, 397 and 385 issubstantially contained within bore 372 of poppet valve 370. Poppetvalve 370 may be considered to have two sections—a first section whichextends from seal 340 (or its equivalent) towards actuator 344 (upwardsin FIG. 8A) and a second section which extends from seal 340 away fromvalve actuator 344 (downwards in FIG. 8A). The pressure relief valveaccording to the present invention is contained substantially within thesecond section of poppet valve 370. This permits the relief valve to belarger and to have a larger (and hence stronger) biasing spring 385.This, in turn, allows the provision of a relief valve having a higherpressure rating—i.e., a higher cracking pressure—than would be feasiblewith a relief valve sized to fit within the first section of poppetvalve 370.

Although the invention has been described in detail with reference tocertain preferred embodiments, variations and modifications exist withinthe scope and spirit of the invention as described and defined in thefollowing claims.

1. A poppet valve for a hydraulic coupling comprising: a poppet valvebody having first, sealing portion in the shape of a conical frustum anda second, generally cylindrical portion adjacent the first portion; acentral axial cavity in the poppet valve body that is substantiallyclosed at a first end thereof and open at an opposing second end; apressure-relief valve within that portion of the central axial cavitythat is situated in the second, generally cylindrical portion of thepoppet valve body.
 2. A poppet valve as recited in claim 1 wherein thepressure-relief valve is a ball check valve.
 3. A poppet valve asrecited in claim 2 wherein the pressure-relief valve is a spring-loadedball check valve.
 4. A poppet valve as recited in claim 1 wherein thepressure-relief valve is configured to open at a predetermined fluidpressure differential between the first end of the poppet valve body andthe second end of poppet valve body.
 5. A poppet valve as recited inclaim 1 further comprising a valve actuator connected to the first endof the poppet valve body and having a fluid passageway connecting theexterior of the valve actuator to the central axial cavity.
 6. A poppetvalve as recited in claim 5 wherein the valve actuator is substantiallycylindrical and the fluid passageway is open to the cylindrical sidesurface of the valve actuator.
 7. A poppet valve as recited in claim 1wherein the valve sealing portion of the poppet valve body comprises ametal-to-metal seal.
 8. A poppet valve as recited in claim 1 wherein thevalve sealing portion comprises an annular polymer seal retained on theexterior of the first section of the valve body.
 9. A poppet valve asrecited in claim 8 wherein the polymer seal comprises an elastomer. 10.A poppet valve as recited in claim 1 wherein the poppet valve body isconfigured for sliding engagement within the central cavity of ahydraulic coupling member against a helical compression spring retainedbetween the poppet valve body and a spring seat retained within thehydraulic coupling member.
 11. A poppet valve as recited in claim 1wherein the poppet valve body comprises at least one annular, radialspacer projecting from the outer surface of the body which spacercomprises a plurality of axial slots at the periphery of the radialspacer.
 12. A poppet valve as recited in claim 1 wherein the poppetvalve body comprises at least one annular, radial spacer projecting fromthe outer surface of the body which spacer comprises a plurality ofthrough holes open at opposing, axial ends of the radial spacer.
 13. Apoppet valve as recited in claim 1 further comprising at least oneradial fluid passageway in the poppet valve body in fluid communicationwith the exterior surface of the poppet valve body and the central axialcavity in the poppet valve body.
 14. A poppet valve as recited in claim1 further comprising a filter in fluid communication with the pressurerelief valve.
 15. A poppet valve as recited in claim 1 furthercomprising a threaded portion of the central axial cavity and springseat in threaded engagement with the central axial cavity which springseat comprises a first end configured to receive a poppet valve actuatorspring and an opposing second end having a ball valve seat and a fluidpassageway connecting the first end to the ball valve seat.
 16. A poppetvalve as recited in claim 15 wherein the ball valve seat comprises afrusto-conical section of the fluid passageway.
 17. A poppet valve asrecited in claim 15 further comprising a spring-loaded ball actuatorsized as configured to slide longitudinally within the central axialcavity and bear against a ball on the ball valve seat.
 18. A poppetvalve as recited in claim 17 further comprising at least one fluidpassageway connecting one axial end of the actuator to an opposing axialend of the actuator.
 19. A poppet valve as recited in claim 15 furthercomprising a seal adjacent the threaded portion.
 20. A poppet valve asrecited in claim 19 wherein the seal is an O-ring seal.
 21. A femalehydraulic coupling member comprising: a generally cylindrical bodyhaving a central, axial bore; a receiving chamber at a first end of thecentral axial bore configured to receive the probe member of acorresponding male hydraulic coupling member; fluid connection means atan opposing second end of the central axial bore configured to connectto a hydraulic fluid conduit; and, a pressure-relieving poppet valvewithin the central axial bore intermediate the first end and second endthereof that comprises; a poppet valve body having first, sealingportion in the shape of a conical frustum and a second, generallycylindrical portion adjacent the first portion; a central axial cavityin the poppet valve body that is substantially closed at a first endthereof and open at an opposing second end; a pressure-relief valvewithin that portion of the central axial cavity that is situated in thesecond, generally cylindrical portion of the poppet valve body.
 22. Amale hydraulic coupling member comprising: a generally cylindrical bodyhaving a central, axial bore; a probe member at a first end of thegenerally cylindrical body configured to engage the receiving chamber ofa corresponding female hydraulic coupling member; fluid connection meansat an opposing second end of the generally cylindrical body and in fluidcommunication with the central axial bore configured to connect to ahydraulic fluid conduit; and, a pressure-relieving poppet valve withinthe central axial bore intermediate the first end and second end thereofthat comprises; a poppet valve body having first, sealing portion in theshape of a conical frustum and a second, generally cylindrical portionadjacent the first portion; a central axial cavity in the poppet valvebody that is substantially closed at a first end thereof and open at anopposing second end; a pressure-relief valve within that portion of thecentral axial cavity that is situated in the second, generallycylindrical portion of the poppet valve body.